In my U.S. Pat. No. 4,971,328, I disclosed a golf swing training device in the configuration of a conventional club with a foreshortened shaft, which includes a light source only in the head to emit a beam of light to trace an arc of light across the ground as the club is swung to thereby provide a mental image to the golfer of the precise club path.
Prior art devices are designed to assist a golfer in improving the golfer's swing by providing visual assistance to trace and thereby examine his/her swing, to minimize or eliminate technique problems, such as hooking or slicing of the ball.
One such device, U.S. Pat. No. 3,070,373 issued to Donald K. Mathews et al, discloses an attachment to the club shaft. The attachment comprises a light source for projecting a collimated pencil beam of light downwardly onto the ground just ahead of the club and between the golfer and golf ball so that a visually perceived trace of club travel is given so that the golfer and/or instructor are informed of the golfer's swing. This device however, suffers from various drawbacks, such as aesthetics (due to the fact that the device is attached to the shaft), transportation difficulties (due to the fact that the device is powered by a large battery pack which rests on the ground near the golfer), etc.
The device disclosed in U.S. Pat. No. 3,953,034 issued to Rodney Nelson discloses a laser beam golf club training device which has a laser beam source attached to or mounted within the club shaft. The laser beam is reflected by a mirror attached to the club head to produce a fan of light to indicate the club head path. It is believed that the possibility of breakage of the convex mirror from which the laser beam must be reflected is a potential drawback to this device.
The device disclosed in U.S. Pat. No. 4,456,257 issued to Sonnie Perkins, discloses a golf swing training device which has a light source attached to the club shaft which emits two light beams lengthwise of the shaft to intersect the ground. The light source is wired to a battery pack which is clipped onto the golfer. The attachment of the light source to the shaft and the requirement that the golfer be wired to the device, thereby decreasing flexibility and increasing awkwardness, are believed to be potential disadvantages to this device.
In the training device disclosed in U.S. Pat. No. 2,158,211 issued to Matthew Aitken, the club head contains a light source and a pivoted battery support. The device is designed to permit a golfer to determine whether the golf club swing speed is proper. The two-piece shaft is enclosed at the joint by a flexible spring. When the club is swung at the correct speed, due to centrifugal force, the battery moves into engagement with the electrical contact and illuminates the electric bulb. Further, the shaft sections pivot with respect to one another due to angular acceleration imparted to the club by the golfer. This device also suffers from poor aesthetics and is believed to be much more complex than the instant invention.
U.S. Pat. No. 3,070,373 issued to Mathews et al. discloses a visual swing indicator which is attached to the shaft of a standard golf club near the club head and comprises a light source projecting a narrow or collimated beam of light downwardly from the club to trace the light beam the ground to show the movement of the club head.
Other golf training devices include generally those disclosed in U.S. Pat. No. 3,677,553 issued to Eric Moore and U.S. Pat. No. 3,820,795 issued to David Taylor, which disclose golf club heads with lights indicating a golfer's swing, the latter further disclosing a battery for the light mounted within the golf club shaft.
The use of ultraviolet light and luminescent strips on a golf club head or chemical light on a golf club head are disclosed in U.S. Pat. No. 3,649,028 issued to Eugene Worrell.